Currently, light sources such as LEDs (light emitting diodes) can be used in many applications, such as traffic lights, backlight for LCD (liquid crystal display) TVs, computer monitors, etc. In conventional LED driven systems, linear regulators can be used to drive the LEDs. However, a considerate amount of power may be dissipated on the linear regulators, which may reduce the efficiency of the regulators. In addition, the conventional regulators may not regulate an output current to a desirable level accurately enough.